1. Field of the Invention
This invention relates to a magnetic head for recording/reproduction constructed so as to be capable of performing recording and reproduction of recording data for a discrete track-type magnetic recording medium on which a plurality of data recording tracks are formed, a magnetic recording medium for such magnetic head for recording/reproduction, and a recording/reproduction apparatus constructed so as to include the magnetic head for recording/reproduction and the magnetic recording medium.
2. Description of the Related Art
A discrete track-type recording medium (hereinafter also referred to as a “discrete track medium”) on which a plurality of magnetically separated, concentric data recording tracks (hereinafter “tracks”) are formed has been developed as a recording medium capable of high density recording. This discrete track medium can be mounted in an HDD (Hard Disk Drive) for example, and various types of recording data can be magnetically recorded via a magnetic head for recording/reproduction (hereinafter also referred to simply as a “magnetic head”). In this case, by forming non-magnetic parts, such as grooves, between respective tracks on a discrete track medium, an expansion of the effective recording track width due to stray fields of the magnetic head is avoided, and there are fewer instances of a recording of recording data onto adjacent tracks or a reproduction recording data recorded on adjacent tracks (i.e., “crosstalk”). Accordingly, since the formation pitch of respective tracks (hereinafter also referred to as “track pitch”) can be narrowed, it is possible to record recording data at a high density.
As one example of a recording/reproduction apparatus that includes this type of discrete track medium and a magnetic head, a magnetic disk apparatus constructed so as to include a magnetic disk (1) and a magnetic head (H) is disclosed by Japanese Laid-Open Patent Publication No. H06-111502. In this type of recording/reproduction apparatus, during the recording and reproduction of recording data, when a servo pattern (Ps) formed on the magnetic disk is read, the servo mechanism moves the magnetic head (i.e., performs servo control) based on a servo detection signal outputted from the magnetic head so that the magnetic head traces a center (Tc) of a track. On the other hand, the same publication discloses that in order to avoid tracking errors, a magnetic effective reproduction head width of the magnetic head (a magnetic read width Wr), a track pitch (TP) of the magnetic disk, and a width of the servo pattern (Ts) should be designated so as to satisfy predetermined standards. More specifically, the sizes of the effective reproduction head width and the track pitch are designated as being approximately equal, and a width of the servo pattern is designated as being approximately equal to the track pitch or an integer multiple of the track pitch. By doing so, even if the magnetic head becomes displaced to a certain extent from a center of a track during servo control, there is no decrease in the output change of the tracking error signal so that tracking errors can be avoided.
However, as a result of analyzing conventional magnetic disk apparatuses, the present inventor discovered the following problem. That is, in conventional magnetic disk apparatuses, the respective sizes of parts of the magnetic disk and the magnetic head are designated with the main focus being on avoiding tracking errors. Here, if the respective sizes of the parts are designated when a recording/reproduction apparatus is designed, it is necessary to designate the respective sizes of the parts of the magnetic disk and the magnetic head not only to avoid tracking errors but also to avoid recording errors for recording data on a target track and reproduction errors for recording data read from a target track (hereinafter such errors are also referred to as “recording and reproduction errors”). In this type of magnetic disk apparatus (recording/reproduction apparatus), even if tracking servo control is performed for the magnetic head by a servo mechanism, the position of the magnetic head with respect to the recording track will fluctuate within a range of a predetermined displacement (a so-called “off-track width”) due to factors such as a reading precision of the servo pattern by the magnetic head and errors in a movement control amount of the magnetic head set by the servo mechanism. On the other hand, the same publication discloses that the effective reproduction head width is set wider than the recording track width (Tw) and a magnetic effective recording head width (the effective write width Ww) is set wider than the recording track width. However, when the effective recording head width and the effective reproduction head width are set only slightly wider than the recording track width, there are cases where part of the recording track in the width direction is not included in the ranges of the effective recording head width and the effective reproduction head width of the magnetic head when the magnetic head is in a displaced state. In such a state, there are cases where it is difficult to sufficiently magnetize the recording track during the recording of recording data (i.e., it is difficult to properly record the recording data) and/or to properly read a magnetic signal recorded on a recording track when reproducing the recording data. In this way, with a conventional magnetic disk apparatus, there has been the problem that it has been difficult to reliably prevent recording and reproduction errors from occurring.
On the other hand, by setting the effective reproduction head width and the effective recording head width sufficiently wider than the recording track width, it is possible to include the entire width of the recording track in the ranges of the effective recording head width and the effective reproduction head width of the magnetic head even when the magnetic head has become displaced with respect to the recording track by a certain amount. Accordingly, when such a construction is used, it is possible to avoid recording and reproduction errors. However, to simultaneously avoid recording data on adjacent tracks and reproducing recording data recorded on adjacent tracks while avoiding recording and reproduction errors by setting the effective recording head width and the effective reproduction head width wider than the recording track width, it is necessary to widen the grooves located between respective tracks (i.e., to increase the track pitch) to a certain extent so as to prevent positions of the effective recording head width and the effective reproduction head width of the magnetic head from overlapping the adjacent tracks. This means that with a conventional magnetic disk apparatus, there is the problem that it is difficult to record recording data with a high density while avoiding recording and reproduction errors, recording on adjacent tracks, and reproduction from adjacent tracks.